Natural radionuclides in the South Indian foods and their annual dose

The study was carried out to evaluate the radioactivity concentration in the food crops grown in high-level natural radioactive area (HLNRA) in south west India. Food samples collected were analysed by means of a gamma spectroscopy and estimated annual dietary intakes of the radioisotopes 226Ra, 228Ra, 228Th and 40K. The annual intake of the food stuffs was estimated on the basis of their average annual consumption. Calculations were also made to determine the effective dose to an individual consuming such diets. The intakes of these radionuclides were calculated using the concentrations in south Indian foods and daily consumption rates of these foods. Daily intakes of these radionuclides were as follows: 226Ra, 0.001–1.87; 228Ra, 0.0023–1.26, 228Th, 0.01–14.09 40K, 0.46–49.39 Bq/day. The daily internal dose resulting from ingestion of radionuclides in food was 4.92 μSv/day and the annual dose was 1.79 mSv/yr. The radionuclides with highest consumption is 40K.